The present invention relates to a bag of flexible plastic film and more especially to such a bag which is used as a can lining.
It is known to line cans with bags prior to filling cans with foodstuffs, especially ham, so that the packaged food is not in direct contact with the wall of the can. For this purpose, the bag, usually a bag of plastic film, is inserted into the can in such a manner that it closely fits the inner wall of the can. Then the portion of the bag projecting beyond the opening of the can is folded back over the edge of the can opening. This is necessary to facilitate filling of the bag. After filling, the doubled-back portion of the bag is drawn from the edge of the can opening and is used for covering the goods placed in the can. Finally, the can is closed with a lid, optionally under reduced pressure and at an elevated temperature.
Bags hitherto used for lining cans have normally consisted either of two identical, rectangular sheets of film which were superimposed upon each other and joined along their two long sides and one of the narrow sides, for example by welding or heat sealing, or they have been formed from a tube of plastic material one end of which was closed by welding or heat sealing. As a third alternative, it is possible to join the superposed edges of a semi-tubular film to form the bag.
As already mentioned, the dimensions of these bags must be such that they closely fit the wall of the can when filled.
These known bags have the disadvantage that, owing to the inadequate flexibility of their material, they cannot easily be stretched beyond the inner circumference determined by the can. Consequently, it is difficult for the portion of the bag projecting above the can to be folded back over the edge of the can opening.